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Net Blotch of Barley

What we do

The net blotch team is trying to reduce the economic impact of net form and spot form net blotch – two closely related barley diseases responsible for over 30% of all fungal disease losses.

Our research uses a combination of genetic, genomic and proteomic approaches to isolate effector proteins and to understand the disease. The research covers detection of new resistance genes, cytology, resistance gene identification, comparative mapping, genetic mapping, gene expression, bioinformatics and protein separation.

Why we do it

Without any control measures in place, losses from both net form and spot form net blotches would exceed $300 million, with spot form net blotch rated as the most costly disease affecting barley in Australia (Murray and Brennan, 2010).

Net form net blotch is caused by fungal pathogen Pyrenophora teres f. teres, while the spot form net blotch is caused by P. teres f. maculata. Both diseases are characterised by spreading necrosis (cell death) at the infection site, through secreting ‘effectors’ – toxic proteins. By isolating individual effectors and infiltrating them onto different barley varieties, their interaction with susceptible barley loci can be more easily recognised.  This allows breeding programs to rapidly discard sensitive varieties of barley, and only select varieties with resistance genes against the diseases.

A recent outcome

Candidate effector genes causing net form net blotch on barley have been identified using its fungal genome sequence. Their proteins are now being isolated and infiltrated onto barley leaves, to pinpoint effector genes which can then be used in breeding programs.

Net form of Net Blotch

Spot form of Net Blotch (Credit: GRDC)